The effects of fencing uniforms (U) on thermoregulatory responses were analyzed in both practical field investigation (PFI) and laboratory experiment (LE) . In PFI, six fencers (college-aged) performed regular fencing practice wearing U and wearing a short-sleeved shirt and pants (T) in summer. Rectal temperature (Tr), chest skin temperature (Tch), mask temperature (Tmk), heart rate (HR) and sweat rate (SR) were measured during fencing practice. In LE, seven male college-aged subjects performed three sessions of 20-min cycling at light intensity (250 W/m²) in a room temperature maintained at 28 WBGT (wet bulb globe temperature) . Esophageal temperature (Tes), mean skin temperature (Tsk), mean body temperature (Tb), HR, and SR were measured during exercise wearing U and in a semi-nude condition (N) . In both PFI and LE, increases in Tch, Tsk, Tb, Tes, Tr and SR were significantly (p<0.001) greater when wearing U than when wearing T and N. In PFI, the maximal value of Tr correlated significantly with the maximal values of Tch (r=0.513, p<0.001) and SR (r=0.635, p<0.001) during practice wearing U and T. In LE, positive correlations between Tsk and Tes (r=0.797, p<0.001), and between Tb and SR (r=0.658, p<0.02) were found at the end of exercise wearing U and N. In PFI, although the Tsk decreased within a few minutes of a decrease in Tmk, a significant relationship between the decrease in Tmk and Tsk or Tr was not observed during fencing practice. These results demonstrate that when wearing U, a higher skin temperature induces core temperature elevation, and higher skin and core temperatures are associated with increases in SR and HR during exercise in a hot environment. Thus, wearing light clothing during exercise, and taking off the fencing jacket and mask during rest periods would be recommended to reduce the heat stress during fencing practice in hot environments.